the story started like this. After graduation i started my work in LA and lived alone. i thought of getting an alarm system and my parents asked me to do that too, but i was not that serious about it. One day, i received a call, telling me that someone was in my house. i was worried and rushed into home, finding out that my house got robbed. I knew if i will not sleep well and worried my home would be robbed again if i don't buy a security system.. so i went to looking into local stores and searched online, and finally got one. pretty easy to install. now i feel safe again. and i can have a good sleep at night. a security camera may cost you much, but don't have one will cost you more. from this experience, i also learned some security cameras self-installing knowledge. if anyone is interested, i would like to share.

Anyway your alarm can help keep you safer and notify you sooner and possibly scare away the person but it won't 100% prevent you from ever getting robbed or broken into again.

It may not be 100% preventative but it comes real close, especially if you have signs displayed announcing an alarm system.

I have a friend who was hit twice in 2 months before installing an alarm.

His 13 year old daughter came home from school, she entered the house, went to the bathroom with the door open while the bad guys were in the house. She didn't know why the electronics were piled by the back door.

She exited the house to get the mail and when she turned back saw 2 guys in the house. She went to neignbors, called police but they got away. 2 months later thieves struck again.

I don't know how many alarms are sold immediately after a break in but it had to be high.

The sign does 98% of the work and your neighbours without an alarm/sign do the other 1%... Then you have the 1% that don't give a crap if you have an alarm or not but you usually have to flash something expensive or leave a door or window open or something to get that kind of attention.

I think most people who don't believe in having an alarm come over (and sometimes go overboard) after a break in.